Surface preparation belongs in the sample record because a photograph cannot explain everything that happened before it was taken. Two similar-looking blanks may have different documented preparation histories.
Describe the actual sequence
Record the sample identifier and the preparation steps that were actually performed, including an explicit none recorded entry when the history is unavailable. Use only preparation methods allowed by the relevant material and equipment documentation. This note is not a recommendation to apply a solvent or add a coating.
Keep before and after photographs tied to the same sample identifier. Record when each image was captured relative to preparation and engraving. If the preparation history differs between two specimens, make that difference visible in the comparison caption rather than presenting them as equivalent starting points.
Keep conclusions narrow
A useful record might say that one sample had a documented preparation step and the other did not. It cannot establish that the step caused a better result without a suitable comparison. Unknown coatings or residues are reasons to resolve material suitability before testing. Do not turn a visually attractive sample into a general material guarantee.
Browse related planning notes in /updates/.